Since 1979 a new Acquired Immune Deficiency Syndrome has been observed in homosexual and bisexual males, male and female intravenous drug abusers, male and female Haitians, hemophiliacs, and intimate contacts of the aforementioned. Immunologically, the Acquired Immune Deficiency Syndrome is marked by a devastating depression in cellular immune function with subsequent development of multiple severe opportunistic infections. This project involves evaluation of the modified methylene blue stain as a tool for detecting organisms in infected tissues and secretions.